Question: Which Of The Following Is Least Resistant To Antimicrobial Agents?

How do you destroy prions?

They can be frozen for extended periods of time and still remain infectious.

To destroy a prion it must be denatured to the point that it can no longer cause normal proteins to misfold.

Sustained heat for several hours at extremely high temperatures (900°F and above) will reliably destroy a prion..

Which concentration of ethanol is the most effective bactericide?

50-80%All Answers (40) c) An ethanol percentage of 50-80% destroys the cell wall/membrane of bacteria by denaturing their proteins and dissolving their lipids. Effective against most bacteria, fungi and some viruses; ineffective against bacterial spores.

How do you disinfect prions?

Immerse in 1N NaOH or sodium hypochlorite (20,000 ppm available chlorine) for 1 hour; remove and rinse in water, and then transfer to open pan and heat in a gravity displacement (121°C) or porous load (134°C) autoclave for 1 hour; clean; and subject to routine sterilization.

What prion means?

The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain.

Why are prions resistant to most antimicrobial methods?

Prion aggregates are stable, and this structural stability means that prions are resistant to denaturation by chemical and physical agents: they cannot be destroyed by ordinary disinfection or cooking. This makes disposal and containment of these particles difficult.

Which microbes are the most resistant to autoclaving?

The non-lipid containing viruses and bacteria with a waxy coat occupy a midrange of resistance. Spore forms are the most resistant. Autoclaving provides heat and moisture as the damage factors to destroy organisms.

What are the disadvantages of autoclave?

Disadvantages of Autoclaving in Dentistry:Moisture retention.Carbon Steel can get damaged due to moisture exposure.Only Stainless Steel instruments and plastics which can bear the heat be sterilized.

What are examples of antimicrobial agents?

The main classes of antimicrobial agents are disinfectants (non-selective agents, such as bleach), which kill a wide range of microbes on non-living surfaces to prevent the spread of illness, antiseptics (which are applied to living tissue and help reduce infection during surgery), and antibiotics (which destroy …

How do antimicrobials work against bacteria?

Antimicrobials work at a cellular level to continually disrupt and prevent the growth of microorganisms. By creating an inhospitable environment for microorganisms like bacteria, mold and mildew, antimicrobials protect everyday products like countertops, toys, surface coatings, textiles and hospital equipment.

Which of the following is most resistant to antimicrobial agents?

Key PointsEndospores are considered the most resistant structure of microbes. They are resistant to most agents that would normally kill the vegetative cells they formed from.Mycobacterial infections are notoriously difficult to treat. … Fungal cells as well as spores are more susceptible to treatments.

What bacteria is hardest to kill?

While the Gram-positive bugs methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile are the most well-known drug-resistant bacteria, many Gram-negative species are particularly hard to treat because they have an extra outer membrane that shields them from drugs.

What are the 5 major targets of antimicrobial agents?

There are five main antibacterial drug targets in bacteria: cell-wall synthesis, DNA gyrase, metabolic enzymes, DNA-directed RNA polymerase and protein synthesis. The figure shows the antimicrobial agents that are directed against each of these targets.

How does moist heat kill microbes?

Moist Heat: Kills microorganisms by coagulating their proteins. In general, moist heat is much more effective than dry heat. Boiling: Heat to 100oC or more at sea level. Kills vegetative forms of bacterial pathogens, almost all viruses, and fungi and their spores within 10 minutes or less.

What bacteria Cannot be killed by antibiotics?

Bacteria resistant to antibioticsmethicillin-resistant Staphylococcus aureus (MRSA)vancomycin-resistant Enterococcus (VRE)multi-drug-resistant Mycobacterium tuberculosis (MDR-TB)carbapenem-resistant Enterobacteriaceae (CRE) gut bacteria.

What is the strongest antibiotic on the market?

The world’s last line of defense against disease-causing bacteria just got a new warrior: vancomycin 3.0. Its predecessor—vancomycin 1.0—has been used since 1958 to combat dangerous infections like methicillin-resistant Staphylococcus aureus.

What are the 4 targets of antimicrobial agents?

Five bacterial targets have been exploited in the development of antimicrobial drugs: cell wall synthesis, protein synthesis, ribonucleic acid synthesis, deoxyribonucleic acid (DNA) synthesis, and intermediary metabolism.

Which of these microbes is least susceptible to microbial control agents?

Enveloped viruses are less susceptible to microbial control than are nonenveloped viruses.

What is the most resistant microorganism?

10 most dangerous antibiotic-resistant bacteriaStaphylococcus aureus (MRSA) First Documented: 1884.Burkholderia cepacia. First Documented: 1949. … Pseudomonas aeruginosa. First Documented: 1872. … Clostridium difficile. First Documented: 1935. … Klebsiella pneumoniae. First Documented: 1886. … Escherichia coli (E. coli) … Acinetobacter baumannii. … Mycobacterium tuberculosis. … More items…•